Acetonitrile (CH3CN) is a staple in many chemical and analytical laboratories, but its diverse applications necessitate a clear understanding of its specifications. For B2B buyers aiming to buy Acetonitrile solvent, knowing what to look for in product specifications can ensure optimal performance and cost-effectiveness. This guide focuses on critical parameters for both analytical and synthesis applications, emphasizing how to engage with a reliable manufacturer in China.

Purity and Assay: The most fundamental specification is purity, typically measured by Gas Chromatography (GC). For HPLC and UHPLC applications, a minimum assay of 99.8% or 99.9% is standard, often referred to as HPLC grade or gradient grade. This ensures minimal interference with sensitive detectors. For synthesis, while purity is still important, slightly lower grades might be acceptable depending on the reaction's sensitivity. Always verify the minimum assay percentage specified by the supplier.

Water Content: Water can significantly impact chemical reactions and chromatographic separations. Specifications for water content in Acetonitrile are crucial, especially for anhydrous applications or sensitive chromatography. Typically, HPLC grade Acetonitrile will have a very low water content, often less than 0.02%. Karl Fischer titration is commonly used to determine this value.

UV Transmittance/Absorbance: In HPLC, the UV detector's performance is heavily influenced by the mobile phase. Acetonitrile used for HPLC should exhibit high UV transmittance or low UV absorbance at relevant wavelengths (e.g., 210 nm and 254 nm). Specifications might state maximum absorbance values (e.g., ≤ 1.0 mAU at 210 nm) or minimum transmittance percentages at specific wavelengths (e.g., ≥ 90% at 230 nm). This is a critical indicator for gradient chromatography.

Residue on Evaporation: Another key indicator of purity is the residue left after evaporation. Low residue values (e.g., ≤ 2.0 mg/L) are essential to prevent contamination of analytical equipment or interference in sensitive processes. This is particularly important for semiconductor cleaning applications.

Acidity and Alkalinity: The pH or presence of acidic/alkaline impurities can affect reaction kinetics and sample stability. Specifications usually define maximum limits for free acid (e.g., as CH3COOH) or alkalinity, ensuring neutrality for sensitive applications.

When evaluating an acetonitrile price, remember to compare these specifications. A slightly higher price for a product with superior purity and lower impurity levels can be more cost-effective in the long run, preventing costly experimental failures or production issues. Partnering with a reputable CAS 75-05-8 supplier who transparently provides these details is vital for informed purchasing decisions. Consider a leading manufacturer in China for reliable sourcing and competitive wholesale opportunities when you need to purchase Acetonitrile.